Physicshard · Past Paper
A wire of resistance 4 Ohms is stretched to double its length. What is its new resistance?
A8 Ohms
B16 Ohms
C2 Ohms
D4 Ohms
✓ Correct Answer: B — 16 Ohms
When length doubles (L'=2L), the area halves (A'=A/2) because volume is constant. New R' = ρ(2L)/(A/2) = 4R = 4*4 = 16 Ohms.
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